1. Field of the Invention
The present invention relates to steam carpet cleaning machines.
2. Discussion of the Prior Art
The machine of the present invention relates to portable hot water extractors, also called portable steam carpet cleaners. These machines have almost always been self-contained. By self-contained it is meant it has a holding tank for its cleaning water and a large recovery tank 12 for the dirty water. These machines work by pulling water from the holding tank with a high pressure pump, spraying it on the carpet and recovering it with a vacuum source forming a water pick-up area.
Traditionally, the main problem with steam carpet cleaning machines has been their over wetting of carpets. This over wetting is due to the inability of these machines to generate enough vacuum or suction at the carpet. This inability has led to restricting the amount of water used in the cleaning process. This restriction in water flow has limited the cleaning ability of these machines.
The water recovery systems within these machines produces much less vacuum or suction at the carpet than the machine described herein, even though they often use the same type of vacuum motor. This is caused by three reasons:
1) The much longer distance between their vacuum motor and water pick-up;
2) The comparatively large volume of air contained in their recovery tanks;
3) The comparatively large area the vacuum acts upon on the inside of their recovery tanks.
All steam carpet cleaning machines have recovery tanks. These are the tanks which hold the recovered water sprayed onto the carpet. Other than the machine of the present application, there are only two other known types of portable steam carpet cleaning machines. Both of these types have similar recovery tanks:
1) Self-Contained Pull Behind Machines which have recovery tanks in the 7 to 10 gallon range;
2) Box and Wand Machines which have recovery tanks in the 10 to 18 gallon range.
The main difference with these two types of machines is that the box and wand has a vacuum hose running from the recovery tank 12 to the cleaning wand. The self-contained pull behind has the cleaning wand connected directly to the recovery tank 12.
How these recovery tanks work is as follows. A vacuum motor capable of generating anywhere from 2 to 4 HP is mounted on the outside of the recovery tank 12. A vacuum hole in the recovery tank 12 allows the vacuum generated by the vacuum motor to enter the tank. When the wand or water pick-up part of the machine makes contact with the carpet, it partially closes the system. The vacuum motor immediately starts removing air from the recovery tank 12. As air is removed from the recovery tank 12 a vacuum or suction is exerted on both the inside area of the vacuum tank and the carpet that is under the water pick-up. This vacuum increases as more and more is removed from the recovery tank 12.
Since all vacuum motors are limited in the amount of air they can remove per minute, it stands to reason that the smaller the volume of air in the recovery tank 12 the faster the vacuum will act at the carpet under the water pick-up. Also since all vacuum motors are limited in the power they can generate, it stands to reason that the fewer square inches this power has to act upon the more vacuum response it will be to the areas that it does act on.
In a large recovery tank 12 much of the power generated by the vacuum motor is wasted by acting on the large inside volume of the recovery tank 12. To get as much vacuum to the carpet as possible, it is vitally important to reduce both the volume and the inside area of the recovery tank 12. By doing this you usually reduce the distance between the vacuum motor and the water pick-up.